COMP 110-001: Introduction to Programming, SSI'15

Description

NOTE: If you want to play the game on the left, you may need to use Firefox to reopen this webpage, because Chrome and safari may not support the java plugin.

You will write a java applet memory game similar to the example above. I have given you a starting program Memory.java where you will have to fill in the missing pieces. The program I have given you has some functionality, make sure you read the comments and understand which pieces you can change and which pieces you should not change.

This is a very hard program and I recommend starting simple and gradually adding more complicated features.

Think of the game board as a 2-dimensional array that holds matching pairs of integers. Each integer will display a circle with a different color on the board.

Build an array that holds the values for your game board. Your board must be random. I recommend writing a method to display the values in your array to make sure they are correct (for example, using MyArrayTest.java).

• Declare and initialize a 4 x 4 2D array that holds integers.
• Your array will need to hold 8 different integers and each integer will need to appear in the array twice. The matched integers will be your memory pairs.
• Your integers need to be randomly located in your array.

Start simple. Declare and initialize a 4 x 4 array and put the integers 0-15 in order in your array. (Display your array to make sure it is correct). Now change the numbers 8-15 to 0-7 (think %). Randomizing the numbers is the hard part and there are many different ways to do this but you will probably want to use Random rnd = new Random(); rnd.nextInt(...). Check Java API if you don't know how to use it.

Mouse Clicking

You have been given code that gets mouse clicks and sets xMouse and yMouse to the location of the mouse click. xMouse and yMouse will range from 0 to 399. You will be using the Graphics class to display your game board. The window is 400 x 400 with (0,0) in the upper left corner. You should think of the board as a visual array with board[0][0] as the top left corner and each square is 100 x 100. To determine which square the user has selected you will need to convert the location of xMouse and yMouse to your array indices. There is a very easy way to do this without using if statements or switch statements. Note: the indices, (i, j), correspond to (y, x), not (x, y). You will need to write a method that determines the current index location the user has selected

Game Display

Once you know which index the user has selected you will need to display a circle (or you can choose other shapes if you want) in the correct square on the board. You can determine the location of your shape by multiplying and adding your current index by numbers.

The color of your shape is determined by the integer in your 2D array. Finish the method displayCircle to draw circles with different colors. The value you will pass in will be board[xIndex][yIndex] (the integer located in the xIndew, yIndex location in the array).

You should start thinking about the game functionality once you have everything else working. There is nothing tricky about the coding; this is just a logic problem. I recommend that you start this section with a piece of paper and pencil and write some pseudocode. Here are some things to think about and consider:

• You need to keep track of every two guesses
• You could use instance variables that keep track of the current guess and the previous guess
• You need to check if the current and previous guesses are the same
• If the user guessed incorrectly you will want the previous shape to disappear. You can do this using the Graphics clearRect method. Look up this method in the Java Graphics class on the web.
• If the user guessed correctly, you should mark those boxes as found. Hence, you may need another 2D array with base type as boolean to record all the correct guesses.
• You may want to make sure the user has not guessed the same box twice
• You may want to check when the game is over
• There are many error checking things that need to be done for this program, however I do not expect you to complete them all

Grading

How to hand in the assignment

• A file named yourlastname_HW4.jar, where yourlastname is your last name. The .jar file should include Memory.java and Memory.class. The same with Lab 3 and Lab 5, use the exsiting MANIFEST file when exporting the jar file, since this is an applet.
• Your java files should have the appropriate header.
• Submit your jar file on Sakai by 11:59pm Friday June 12, 2015.
• Please let me know if you are having any problems about this assignment.